Scientific identify: Isistius brasiliensis 
Scientific classification:
Phylum: Chordata
Class: Chondrichthyes
Order: Squaliformes
Family: Dalatiidae


What does it appear like?
The cookie-cutter is a small shark. An grownup is simply round 50 cm lengthy and as is the way in which with sharks the feminine is bigger than the male. The slender, tapering physique lacks an anal fin and its coloration ranges from gray to gray-brown. The head is compact with eyes close to the entrance. The lips can type an efficient suction cup and half to reveal a formidable complement of enamel.

Where does it reside?
Specimens of this shark have been discovered within the Atlantic and Pacific, usually in tropical waters. The furthest north it has been discovered is Japan, whereas to the south it reaches at the least to Southern Australia. It appears to be extra generally encountered off islands, however has additionally been fished up from open water. It lives at the least 100 m under the waves and might be in a position to plumb depths of at the least three km.

Characteristics

The cookie-cutter shark, with its fl abby little physique, is way from probably the most elegant of the sharks, however as with the vast majority of these marine animals it's a consummate predator and what it lacks in bulk it greater than makes up for in method. As it's an animal of the deep sea it has developed some weird methods of snatching a meal. In one of the alien of earthly habitats, many animals can generate gentle, both as a way of illuminating prey, communication, or deception. Special gentle producing cells are discovered on the our bodies of these animals. The cookie-cutter shark may produce its personal gentle; its underside, other than a collar behind its head, offers off a pale inexperienced/blue luminescence. From under the shark, other than its collar, would merely mix in to the diff use, pale gentle scattering into the depths from above. To a big predatory animal swimming under the shark the collar would stand out like a beacon, resembling to all intents and functions a small fish. Thisoptical phantasm can be much more eff ective if the massive animal was swimming under a shoal of cookie-cutters. Fooled into considering these shapes are some tasty morsels the big predatory animal, be it a big fish or marine mammal would head straight for it. Like the marine equal of a matador, the tiny shark deftly swims out of the way in which earlier than the predator strikes and utilizing the aggressor’s ahead momentum for added buy the shark latches onto the animal with its suction-cup lips earlier than plunging its enamel into its sufferer’s fl esh. The dentition of the shark is on no account run of the mill. Its capacious mouth bristles with 25–32 rows of pointed, triangular enamel, the entrance set of which look as if they belong in a miniature man-lure. The decrease set are bigger than the uppers and as they sink into the prey, its ahead momentum and a fast pirouette gouge out a mouth-sized plug of pores and skin, fats and muscle. Thislump of tissue is cradled by the higher enamel and then hooked by the smaller higher enamel earlier than being wolfed down. The scar left by one in every of these assaults resembles the neat melancholy left in a melon after it has been assaulted with a melon scoop.

Key Facts

  • The cookie-cutter and its shut relative, the big-toothed cookie-cutter, are sorts of dogfish with distinctive predatory ways bordering on the parasitic. As they reside at such nice depths little is thought about them. The solely recognized specimens have been these present in trawl nets.
  • Although the cookie-cutter is a small shark it's removed from the smallest species. The spined pygmy shark is reputed to be the smallest, measuring a mere 22 cm.
  • Female cookie-cutter sharks produce eggs that hatch inside their physique. The off spring are nourished by their giant yolk sac. Six to 12 younger are produced at a time and upon rising from their mom, the younger are absolutely impartial and can hunt nearly immediately.
  • The skeleton of the cookie-cutter shark is sort of closely calcified, which most likely helps it regulate its buoyancy within the ocean depths. Its weight loss plan incorporates little in the way in which of calcium, subsequently when its worn enamel are prepared to get replaced they're swallowed and digested for the calcium they comprise. In many different sharks, the enamel are merely discarded and fall to the seabed.
  • The liver of this shark is giant and oily and is an eff ective buoyancy support so the animal can fl oat within the water column with out a lot eff ort.
  • Many sorts of sea creature bear the scars of a gathering with a cookie-cutter shark. Even submarines aren't protected from their gnashing enamel. The rubber-lined sonar domes of these vessels are often pocked with the feeding gouges of cookiecutters who would have been undoubtedly dissatisfied to discover themselves with a mouth-stuffed with rubber as a substitute of scrumptious blubber.
  • Like most deep-sea animals, the cookie-cutter shark makes every day, vertical migrations over distances in extra of two km. During the day, they continue to be in deep water, in what is named the deep scattering layer, however through the night time they swim up into shallower water, maybe to inside a couple of meters of the floor.
  • The deep scattering layer is inhabited by many animals and is a crucial foraging space for tuna, porpoises, and so forth. It is when these animals go to this twilight zone that they fall prey to the fearsome jaws of the cookie-cutter.
  • Although the cookie-cutter is specialised to feed on bigger marine animals it should additionally eat squids, crustaceans, and different marine invertebrates.
  • It has been reported {that a} cookie-cutter shark offers off its eerie blue-inexperienced glow up to three hours after it has died.